This section provides background information related to the present disclosure which is not necessarily prior art.
An onboard displaying device including a head-up display has been used for a vehicle to form virtual images of information, including traveling speed and warning patterns of a vehicle, transmitted from a liquid crystal display (LCD) panel in front of a front windshield. Generally, a conventional head-up display may have a lighting source located in a rear part of the LCD panel. The lighting source may have a first light emitting diode (LED) group and a second LED group. LEDs in the second LED group may have higher directivity than LEDs in the first LED group and may be located above the LEDs in the second LED group. The LCD panel may receive light emitted from the LEDs through a diffusion plate, and may display high priority information on an entire display surface of the LCD panel. It also may receive light emitted from the LEDs, and may display low priority information on a partial display surface.
In sum, the conventional head-up display may have the lighting source and the LCD panel integrally, and the lighting source and the LCD panel may be accommodated in a cylindrical casing together, which may be placed behind an instrument panel. In such a structure, there may be a concern of thermal damage of the LCD panel due to heat from the second LED group because the second LED may have high directivity so that the second LED may generate high heat. As the directivity of the second LED group may increase, lighting intensity of the second LED group may increase correspondingly. Thus, as the lighting intensity of the second LED group increases, heat generated in the cylindrical casing may increase correspondingly.